The present invention relates to a method of and arrangement for dressing (truing) of grinding wheels with diamond or cubic crystalline boron nitride as grinding material, by means of a diamond dressing tool. More particularly, it relates to such a method and an arrangement in which a diamond dressing tool is connected with a movable machine carriage which has an adjustable feeding speed.
It is known to utilize an electromechanical drive unit for feeding a dressing tool. A NC control or a CNC control can be used for these purposes. Such devices are relatively expensive. Its substantial disadvantage is also that the feeding cannot be performed in many cases as accurately as desired as a result of errors which are produced by mechanical friction and also an insufficient rigidity of the drive system. Moreover, thermal effects such as for example temperature increase in the working space or temperature fluctuations of the grinding disk also undesirably affect the accuracy of the feeding. Since the grinding disk expands during its use as a result of its heating, therefore for a new dressing step it is located after its return to the dressing position in a different location, as compared with the location in which it was initially dressed under lower temperature. Therefore the preliminary developed value for the adjustment of the dressing tool is not reproducible. In the grinding technique there is a requirement to make possible such dressing feed which is reproducible with values lower than 2 micrometer. What is understood here as a dressing feed is the feeding of a dressing tool per each dressing step. If a total dressing feed amounts to 2 micrometers, it is advantageous when this value is subdivided into several individual feeding steps of smaller value, such as for example 4 individual feeding steps each equal 0.5 micrometer. In this approach significantly improved dressing feed can be obtained than in the event of a greater feed. In practice, however, these approaches have not been implemented since the system of cooperation between the grinding wheel and the dressing tool continuously changes especially as a result of deformations which are caused by thermal forces. A dressing output which must be reproducible presumes the exact knowledge of the spatial arrangement between the grinding wheel and the dressing tool, as well as the utilization of a feeding system with highest possible positioning accuracy. What is understood here under the reproducibility is that it must be continuously guaranteed that the same action is produced at different outside conditions during dressing as in the predetermined initial dressing steps.